# GPS Rollover is today. Here’s why devices might get wacky



## GURPS

The Global Positioning System time epoch is ending and another one is beginning, an event that could affect your devices or any equipment or legacy system that relies on GPS for time and location.

Most clocks obtain their time from Coordinated Universal Time (UTC). But the atomic clocks on satellites are set to GPS time. The timing signals you can get from GPS satellites are very accurate and globally available. And so they’re often used by systems as the primary source of time and frequency accuracy.

When Global Positioning System was first implemented, time and date function was defined by a 10-bit number. So unlike the Gregorian calendar, which uses year, month and date format, the GPS date is a “week number,” or WN. The WN is transmitted as a 10-bit field in navigation messages and rolls over or resets to zero every 1,024 weeks.


https://techcrunch.com/2019/04/06/gps-rollover-is-today-heres-why-devices-might-get-wacky/


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## black dog

I'm still using Loran, but charts of Indiana are hard to come by.


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## vraiblonde

Our GPS is always wacky - both Monello's AND mine.  Garmin, btw.  GPS lady sends us all over Hell's half acre to somewhere that's a straight shot.


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## RoseRed

My GPS worked fine today.


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## Yooper

My GPS has been whacky for some time. My primary care doctor suggested a psychiatrist.

So obviously GPS is a medical issue/problem. Why, then, is everyone talking about devices and atomic time and...and...and? 

--- End of line (MCP)


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## black dog

Yooper said:


> My GPS has been whacky for some time. My primary care doctor suggested a psychiatrist.
> 
> So obviously GPS is a medical issue/problem. Why, then, is everyone talking about devices and atomic time and...and...and?
> 
> --- End of line (MCP)


It's probably an inner ear infection.


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## LightRoasted

If I may ...



black dog said:


> I'm still using Loran, but charts of Indiana are hard to come by.


Remember the days of reading a map? Used to have a stack of Atlas map books for each county worked. Now, lost to antiquity.


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## TCROW

LightRoasted said:


> If I may ...
> 
> 
> Remember the days of reading a map? Used to have a stack of Atlas map books for each county worked. Now, lost to antiquity.



ADC still makes their great maps.


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## Yooper

LightRoasted said:


> If I may ...
> 
> Remember the days of reading a map? Used to have a stack of Atlas map books for each county worked. Now, lost to antiquity.



Yup. Wonder - do they still teach that in the military? Hopefully, yes. Must be a real shock to all the kids who really know nothing but GPS.



TCROW said:


> ADC still makes their great maps.



Yup. Use them and the DeLorme topo maps all the time.

--- End of line (MCP)


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## LightRoasted

If I may ...



Yooper said:


> Yup. Wonder - do they still teach that in the military? Hopefully, yes. Must be a real shock to all the kids who really know nothing but GPS.
> --- End of line (MCP)


Dunno. But what happens in the middle of a mission if the batteries die, I wonder, and there are no spares. And how would they call in artillery as well? Also GPS offers no spacial awareness like maps do as one gets when orientating the map to your position, or, triangulating ones position. No what I mean? Having that mapping and location sense in your head as to where you are and which way to go without having to look at the damn thing every five minutes?


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## Yooper

LightRoasted said:


> If I may ...
> 
> 
> Dunno. But what happens in the middle of a mission if the batteries die, I wonder, and there are no spares. And how would they call in artillery as well? Also GPS offers no spacial awareness like maps do as one gets when orientating the map to your position, or, triangulating ones position. No what I mean? Having that mapping and location sense in your head as to where you are and which way to go without having to look at the damn thing every five minutes?


Exactly. When I was a wee lad the artillery gang introduced a new-fangled (har, har - I'm an old guy) computerized, data-linked, automated firing solutions set-up (Tacfire, if I remember correctly). We also got it in the Cav where each platoon had its 4.2 SP mortar track. Of course, we LTs were thrilled b/c who doesn't like new tech?

My Troop Cdr, however, had different ideas. Using words very similar to yours (above) we Plt Ldrs learned to rely on manual calculations for our fire missions rather than using the automated stuff. Regular fire mission or (especially) hip shoot; didn't matter. Which was also fine for our 11C gun bunnies (being infantrymen and not cannon cockers, they found the automated stuff a bit too advanced!).

--- End of line (MCP)


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## GURPS

M-1950 3H field compass 

and a 7.5 min map


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